Researchers in Japan are developing a method of drawing power from blood glucose, mimicking the way the body generates energy from food. Theoretically, it could allow a person to pump out 100 watts - enough to illuminate a light bulb. But that would entail converting all the food eaten by the individual into electricity. In practice, less power would be generated since food is needed by the body. However the scientists say the "bio-nano" generator could be used to run devices embedded in the body, or sugar-fed robots.

The team at electronics giant Panasonic's Nanotechnology Research Laboratory near Kyoto has so far only managed to produce very low power levels. But the scientists ultimately expect to gain much greater performance from the device. The battery is based on an enzyme capable of stripping glucose of its electrons, The Engineer magazine reported.

Dr Kazuo Eda, heading the research, said: "It is like the metabolism of food. Human bodies can process glucose and obtain energy. When glucose is oxidised, electrons can be obtained." He believed bio-nano fuel cells were the next step for researchers after generators powered by hydrogen, natural gas and methanol now being developed for the car and energy industries.

You know, there are hand-cranks to charge up mobile phones and Gameboys... Why not use turbine power? Stick a pair of needles in your arm, one in and one out, and let your heart pump a little generator...

Sounds neat, but quickly and openly recognizes exactly the problem that the Matrix flatly ignored (that it'd take more power to produce the nutrients to keep the humans alive than the humans would produce power; an engine can't produce work to run itself at anything but at least gradually--if not steeply--decreasing efficiency).

I think these things are meant to be good because they tap a convenient source of energy, not because they provide especially cheap power; they're meant to power eg intelligent pills, not to hook up to the National Grid.

Actually, meant to say that myself, and realized I was late for leaving to go to work.

The research is clearly good for implants that need power (both medical and not, though I expect that grandpa's pacemaker and hearing aid will get an update before I get my behind-the-ear VGA-in jack).